Multifarious immunotherapeutic approaches to cure HIV-1 infection

Immunotherapy in the context of treated HIV-1 infection aims to improve immune responses to achieve better control of the virus. To date, multifaceted immunotherapeutic approaches have been shown to reduce immune activation and increase CD4 T-lymphocyte counts, further to the effects of antiretroviral therapy alone, in addition to improving HIV-1-specific T-cell responses. While sterilizing cure of HIV-1 would involve elimination of all replication-competent virus, a functional cure in which the host has long-lasting control of viral replication may be more feasible. In this commentary, we discuss novel strategies aimed at targeting the latent viral reservoir with cure of HIV-1 infection being the ultimate goal, an achievement that would have considerable impact on worldwide HIV-1 infection

Long-Term Non-Progression and Broad HIV-1-Specific Proliferative T-Cell Responses.

Complex mechanisms underlying the maintenance of fully functional, proliferative, HIV-1-specific T-cell responses involve processes from early T-cell development through to the final stages of T-cell differentiation and antigen recognition. Virus-specific proliferative CD4 and CD8 T-cell responses, important for the control of infection, are observed in some HIV-1(+) patients during early stages of disease, and are maintained in long-term non-progressing subjects. In the vast majority of HIV-1(+) patients, full immune functionality is lost when proliferative HIV-1-specific T-cell responses undergo a variable progressive decline throughout the course of chronic infection. This appears irreparable despite administration of potent combination antiretroviral therapy, which to date is non-curative, necessitating life-long administration and the development of effective, novel, therapeutic interventions. While a sterilizing cure, involving clearance of virus from the host, remains a primary aim, a “functional cure” may be a more feasible goal with considerable impact on worldwide HIV-1 infection. Such an approach would enable long-term co-existence of host and virus in the absence of toxic and costly drugs. Effective immune homeostasis coupled with a balanced response appropriately targeting conserved viral antigens, in a manner that avoids hyperactivation and exhaustion, may prove to be the strongest correlate of durable viral control. This review describes novel concepts underlying full immune functionality in the context of HIV-1 infection, which may be utilized in future strategies designed to improve upon existing therapy. The aim will be to induce long-term non-progressor or elite controller status in every infected host, through immune-mediated control of viremia and reduction of viral reservoirs, leading to lower HIV-1 transmission rates

Therapeutic immunisation benefits mucosal-associated invariant T-cell recovery in contrast to IL-2, GM-CSF, and rhGH addition in HIV-1+ treated patients: individual case reports from phase I trial

Mucosal-associated invariant T (MAIT) cell populations are reduced in frequency in HIV-1+ patients, and this disruption is associated with systemic immune activation. Reconstitution of MAIT frequency may benefit HIV-1-infected individuals; however, only recently has in vivo work been endeavored. Treatment with interleukin (IL)-2, granulocyte-macrophage colony-stimulating factor (GM-CSF), and recombinant human growth hormone (rhGH) immunotherapy combined with an HIV-1 vaccine in the context of antiretroviral therapy (ART) has shown to reconstitute CD4 T cell population numbers and function. In this study cryopreserved peripheral blood mononuclear cells (PBMCs) from 12 HIV-1+ patients who were undergoing a combination of HIV-1 vaccine and/or IL-2, GM-CSF and rhGH immunotherapy in conjunction with ART were analyzed to assess the potential of this treatment to promote MAIT cell proliferation. PBMCs were thawed from study baseline, weeks 2 and 48 time points, fluorescently stained for MAIT cell markers, and assessed by flow cytometric analysis. Matched pairs and intergroup results were statistically compared using appropriate methods. MAIT cell frequency was increased from baseline at 48 weeks in participants who received vaccine only, whereas individuals receiving IL-2, GM-CSF, and rhGH immunotherapy with or without vaccine did not show additional benefit. Although IL-2, GM-CSF, and rhGH treatment promotes CD4 T cell reconstitution and HIV-1-specific T cell function, it does not support MAIT cell recovery in patients on suppressive ART. Therapeutic immunization however has a positive effect, highlighting the importance of aiming for balanced promotion of T cell population reconstitution to impact on HIV-1 transmission and pathogenesis